Physics-Based Printhead Designs for Enhanced Electrohydrodynamic Jet Printing

Abstract

As growth in the electronic and biomedical device industries continues on a steep trajectory, the demand for high-resolution fabrication technology will remain at the forefront of innovation. Traditional high-resolution fabrication techniques such as optical lithography, stamp printing, or ink jet printing, each exhibit significant shortcomings in addition to their acknowledged advantages. As such, they are unable to provide a cost effective solution to highly customizable feature fabrication at the micro-scale. Electrohydrodynamic jet (E-jet) printing is a growing printing-based additive manufacturing technology for high-resolution device fabrication. It enjoys the advantages of other additive manufacturing technologies, and is compatible with a large range of materials; thus it is an advantageous choice for electronic fabrication, high-resolution prototyping, and biological component fabrication. Despite these advantages, E-jet is currently limited by two key technical challenges: (1) Low throughput due to challenges with multi-nozzle printing accuracy and lack of integrated sensing and control, and (2) Substrate constraints due to process sensitivity to offset height variations. The research in this dissertation aims to investigate the basic physics behind the electric-field driven ink meniscus to aid in the development of new E-jet printhead designs and printing approaches to overcome the substrate limitation. In this dissertation proposal we will introduce the key process parameters that drive E-jet printing and present our design methodology that has led to 3 different printhead designs with varying capabilities. Through the observation of new printing behaviors associated with the new E-jet printheads, we investigate and analyze the relationships between these new behaviors and different controlling parameters. These studies offer new insights into the physics and dynamics that govern micro-scale E-jet printing, which can further the development of E-jet and printing-based micro-AM processes in general. As research continues, we will apply our findings and knowledge towards the advancement of printing-based micro-AM fabrication of electronics or biological devices in the future.